The present invention relates to an insert for forming openings in concrete structures.
Concrete slabs, or floors are generally formed by casting or spreading a wet concrete mixture usually containing a hydraulic cement, aggregate and water onto a horizontally extending surface upon which the slab of concrete is to be located. The cast or spread mixture is worked or finished so as to remove pockets of entrained air and so as to obtain a desired surface configuration. The wet mixture is then allowed to harden or set to form the final slab or floor. This process becomes somewhat more complicated when it is desirable to locate holes which extend through such slabs or floors. Often, when holes are required to be formed into the concrete structure, the workers fabricating such a structure search out any convenient material at the job site which appears suitable to hold back the wet mixture from the locations where holes are desired. This situation is less than optimal in that the conveniently available makeshift insert may not be sized correctly, or otherwise optimally configured as a concrete floor insert.
Further, it may take job site workers an inordinate amount of time just to locate and construct such make shift inserts. Occasionally, the construction of the makeshift inserts has not been effective to adequately hold back "wet concrete" from an area where a hole is desired. Also, holes created by this type of expedient do not normally have a desired "smooth" or "clean cut" surface configuration.
Concrete floor inserts generally fall within one of two categories. The first category is that of inserts which are designed to be removed from the solidified concrete thereby leaving behind a smooth concrete hole. The second kind of floor insert is designed to remain in the solidified concrete sometimes providing a smoother interior surface than that of bare concrete. However, if a concrete insert is designed to remain in place after the concrete solidifies, it would be necessary to provide such a concrete insert for each hole desired. Most of the concrete floor inserts of the prior art are specifically designed for removal after concrete solidification due in part to cost savings realized through reuse. Thus, there exists a need to provide a permanently embeddable concrete floor insert which can be provided at low cost.